Pellet Feed Coolers

Pellets from dry pelleters may exit at up to 88°C and
17-18% moisture. The temperature must be quickly reduced to
ambient or less and the moisture level to 10-12% or less for
proper storage and handling. Pellets must therefore be cooled
and dried. Moist pellets, if they are going to be converted
to dry pellets, also need drying although their temperature
is not normally much elevated during manufacture.

Coolers/dryers are of two basic types, horizontal and vertical.

In the horizontal type of cooler/dryer (Figure 22) the
pellets are conveyed on a perforated steel mesh or moving
belt through which a cooling air stream is passed. The horizontal
method is best for 'sticky' dry pellets or for moist feeds
(if it is necessary to dry the latter). Heat can also be applied
to the air supplied to horizontal driers for reducing the
high moisture contents of moist feeds to those of dry pellets
for storage. This type of drier is standard in the production
of noodles and spaghetti and other pasta. Horizontal dryers may be very large and are often arranged on several spatial
levels.

In the vertical type of dryer, pellets usually fall by gravity into a chamber through which air is sucked by a fan, see the diagram adjacent: